In recent years, a light emitting device in which a light emitting element typified by an electro luminescence (EL) element and the like is used in a pixel portion instead of a liquid crystal element has been actively developed for flat panel displays. A light emitting device requires no light source such as a back light, therefore, it has the advantages that moving pictures can be displayed with fast response, viewing angle is wide and the like as well as the advantages of low power consumption, small size and light weight. Accordingly, the light emitting device attracts attention for laptop flat panel displays of the next generation, which will provide full color moving pictures.
A light emitting element included in each pixel degrades with time. As a measure against the degradation of a light emitting element with time, for example, in order to improve a reliability of a light emitting element, a technology for controlling light emitting time of a pixel is disclosed (see Patent Document 1 for example). More specifically, a “black” is displayed by an analog video signal, or two electrodes connected to a light emitting element are set at the same potential so that the light emitting element is made in a non-light emitting state.
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-087070